With the rapid development of nuclear industry in China, an increasing number of nuclear power plants (NPPs) are unavoidable to be constructed upon non-lithological foundations. Therefore, it is essential to optimize the current evaluation methods for non-lithological foundation reinforcement plans. By using the Octree discretization method combining with the scaled boundary polyhedron finite element

Damping modification factor (DMF) plays an important role in seismic design and hazard analysis. Many studies have dedicated to the DMF, but the existing formulations still show a quite large scatter. This study proposes a new theoretical approach for analyzing the DMF. The proposed approach models the seismic ground motion with a source-based Fourier amplitude spectrum (FAS) and estimates the DMF

Site period maps at various strain levels were developed for the combined cities of Ottawa and Gatineau in eastern Ontario and western Quebec. These maps were developed to support earthquake response studies in areas containing post-glacial, soft, silty-clayey sediments, which comprise 60% of the urban areas. Approximately 21,700 boreholes and over 1000 surface and downhole geophysical measurements

The principal stresses that occur in soil below ground level often change direction due to engineering activities. A typical example would be the cyclic loading applied by waves and currents onto the foundation of offshore structures. Even though the principal stress rotations (PSR) are recognized as some kind of “loading” that is exerted onto seabed soil, it is ignored in most investigations into

We estimated the spectral decay parameter, kappa (κ) for the Northwest (NW) Himalaya and the Northeast (NE) Himalaya, particularly NE India, using the strong motion records obtained from accelerographs installed in these regions. We estimated κ from the horizontal as well as vertical records from 294 accelerograms (three components). It has been observed that in the NW Himalaya and NE India, the value

The energy-based method is a promising tool for evaluating soil liquefaction potential. In this study, the effects of initial deviatoric stress (qs) and cyclic stress amplitude (qcyc) on soil liquefaction potential in undrained cyclic triaxial tests were evaluated using the energy-based method. The testing results indicate that the required dissipated energy for the onset of liquefaction is influenced

The impact of freeze-thaw cycling on freshly exposed loess is a major concern in design and construction of embankments or earth dams in the Loess Plateau in China. Due to complex nature of loess as compared with the conventional soils such as sand or clay, characterizing the strength of loess to account for this impact is challenging, in particular in the field conditions. In previous research a systematic

To the end of investigating the potential nonlinear soil behavior at 44 strong motion stations during the 2016 Mw7.8 Kaikōura, New Zealand earthquake, we analyzed the modifications of the site response under the strong mainshock recording based on the horizontal-to-vertical spectra ratio, including the shift of the predominant frequency, and three nonlinearity indicators, DNL, ADNL, and PNL. Significant

This paper presents an approach for assessing the failure probability of a road system due to its interaction with landslides induced by the earthquake. The landslide occurrence and failure probability of the road system is estimated by considering the spatial variation of earthquake ground motion. Since significant incoherence in earthquake ground motions is usually observed within the spatial dimensions

Shaking table model tests were carried out to study the seismic behaviors of double box utility tunnel with joint connections and the surrounding soil. The seismic wave obtained from 1952 Taft earthquake was employed as the input in this study, and its PGA has been adjusted to 0.2 g, 0.4 g, 0.8 g, and 1.2 g, respectively. In addition, a series of sine waves with PGA of 0.2 g and frequencies of 5 Hz

Seismic bearing capacity of strip footings placed near c-φ soil slopes is investigated in this work using finite element limit analysis combined with an adaptive remeshing procedure. In the analysis, the so-called pseudo-static approach is employed to quantitatively describe the seismic effects. Based on the method, the upper and lower bounds of the normalized seismic bearing capacity factor p/γB are

Detailed information of soil/rock variability and properties for the entire volume of supporting materials is crucial for the successful design and construction of deep foundations. Traditional invasive testing methods such as the standard penetration test (SPT) and the cone penetrometer test (CPT) only sample a small volume of soil/rock properties near the device's tip. Surface-based seismic methods

The seismic responses of precast concrete structure are studied under the earthquake excitations, by applying the shaking table test on the 12-storey, two-bay, 1/5 scale monolithic prefabricate concrete shear wall structure (MPCSWS), which is designed with the Chinese codes and assembled by the precast elements and cast-in-place boundary elements in the laboratory. The model MPCSWS is subjected to

The Geotechnical Seismic Isolation (GSI) is recently recommended as an innovative base isolation system placed below the foundation of the superstructure for protection from earthquake damages. Low-shear modulus and high damping material such as Sand-Rubber Mixture (SRM) is used for the GSI layer. However, the compressible nature of SRM in the GSI layer leads to low bearing capacity and high settlement

In 2011 off the Pacific coast of Tohoku Earthquake, liquefaction and reliquefaction were observed along 600 km of the Northeast Coast of Japan and the infrastructure in this area experienced severe damage. During the earthquake, the fact that reliquefaction in aftershocks may also cause severe damage to infrastructure draws much attention of the researchers specialized in liquefaction. Researches in

In this study, a series of shaking table tests were carried out based on an irregular cross-section subway underground structure. Further, the development laws of pore pressure, structural strain, acceleration intensity, and the propagation law were analyzed. The results show that the peak acceleration of the surface is attenuated, which reflects the isolation effect of the liquefied soil. The spectral

Soil dynamic parameters such as shear wave velocity and damping ratio are of major interest in earthquake engineering. While the shear wave velocity, directly linked to the shear modulus, can be determined by a number of laboratory and in-situ tests with satisfying accuracy the damping ratio is much more difficult to obtain. Especially the results of in-situ experiments show often large variations

The influence analysis of the site condition is a key issue considered in the seismic design of nuclear power engineering on non-rock sites. To study the soil–structure interaction (SSI) effect of the site conditions on the structural seismic response of nuclear power engineering, we used a CAP1400 nuclear power plant as a case study subject and performed a shake table testing of a soil–structure system

In establishing the numerical model to simulate the saturated soil-structure interaction subjected to dynamic loadings, the absorbing boundary conditions are usually applied to simulate the wave propagation in the field. In this study, a type of viscous boundary in conjunction with the domain reduction method (DRM) is proposed as an advanced absorbing boundary. The performance of this advanced absorbing

The development of collapse fragility curves is an essential requirement for the assessment of the collapse risk of structures. These fragility curves depend on the structural collapse capacity that is evaluated in terms of either the intensity measure (IM) or the damage measure (DM); such as the engineering demand parameter (EDP). In turn, collapse capacity estimates are sensitive to the method employed

Characterizing the potential effect of local site conditions on the amplification of ground motions is a critical aspect of seismic hazard and risk assessment. The aim of this study is to investigate the reliability and the limit of using the average shear wave velocity in the upper 30m of the soil profile vs,30, as single proxy, to characterize seismic site effects for weak and strong events. To this

The modal response of liquid-storage steel tanks and the associated prevailing frequencies in the horizontal impulsive mode of vibration are explored by means of earthquake recordings. To this end, a well-documented case study is employed, referring to an instrumented steel cylindrical tank which is a property of the HEL.PE. Oil Company in the Kalochori area, west of Thessaloniki in Northern Greece

Oil and gas buried steel pipelines are vulnerable to permanent ground displacements, such as those resulting from tectonic fault activation. The dominant failure mechanism is strongly dependent on the type of faulting. The more complex case is the reverse fault type because the crossing pipeline is significantly compressed and bent and consequently, it may fail due to local buckling, upheaval buckling

The main purpose of this study is to estimate the inelastic displacement ratio, C1, of highly damped systems built on soft soil sites. For this purpose, results of linear and nonlinear time history analysis of 79 single-degree-of-freedom (SDOF) systems with damping ratios of 0.05, 0.1, 0.2, 0.3 and post-yield stiffness ratios of -0.01, 0, 0.05 and 0.1 under a large number of ground motion records obtained

Centrifuge modeling has been used to observe some key characteristics of liquefiable soils during seismic motions. If carefully conducted, the results of centrifuge tests can be used for validation of constitutive models and numerical modeling tools. However, a thorough evaluation of numerical models requires knowledge of the soil properties and the uncertainties associated with these properties. Moreover

Adjacent base-isolated buildings with corridor bridges have a large seismic displacement demand in their isolation layer, and therefore are prone to collision. Moreover, seismic wave incidence angles may have a great impact on their seismic collision response, especially for near-fault ground motions that may exhibit strong directionality dependence. This paper studies the impact of seismic wave incidence

Using a set of full-scale free vibration measurements, two separate state of the art identification strategies are implemented for the time domain identification of the modal properties of the superstructure of a three-story base-isolated building. In a first approach, the superstructure is modeled as a fixed-base linear 3-DOF system subjected to the base acceleration measured during the tests. Identification

An accurate absorbing boundary condition (ABC) is proposed to incorporate in the frequency-domain finite element simulation for numerically solving u-U elastic wave equations in horizontally multilayer fluid-saturated porous media. The u-U elastic wave equations are first discretized only along the depth direction in which the material properties are heterogeneous, analytical method using in the remaining

Buried composite pipelines crossing active faults can be deformed significantly due to strike-slip fault movement. Because of the problem complexity arising from material mechanical behavior and imposed large deformation, a numerical analysis was conducted using a nonlinear finite element approach. The lateral displacement incrementally was imposed normal to the pipe axis until one of the pipe layers

To probe into the mechanical behaviour of railway transition zone from the macro-meso aspects, a numerical model of transition zone is built that hybrids the Discrete Element Method (DEM) and Finite Difference Method (FDM). The DEM is utilised to simulate the ballast bed and sleeper, because it can consider the realistic ballast shapes and complex contacts between them. The FDM based on the continuum

Buckling instability has been recently identified as a possible mechanism of pile failure in liquefiable deposits and this failure mechanism is not explicitly mentioned in most design codes. To carry out routine design and checking, it is necessary to reliably estimate the critical buckling load of pile for a given liquefiable site. However, the existing calculation methods for the critical buckling

Single-storey precast reinforced concrete (RC) frame type buildings are mainly preferred in manufacturing plants and storehouses. The behaviour of semi-rigid beam-column connections of the buildings is one of the main sources of uncertainty. The common damages observed after credible earthquakes were falling off large-span beams and large plastic deformations at the column base. New generation Lead

Nonlinear structural response of buried continuous pipeline undergoing strike-slip fault rupture, i.e., where soil masses get displaced in the horizontal plane along a fault line, is studied in a detailed manner. A detailed analysis technique employing ABAQUS/Standard with implicit formulation to study the behavior of buried continuous pipelines crossing fault movements is proposed and established

Filtering is one of the critical steps of earthquake ground motion processing before its application to engineering practice, and high-pass filtering is particularly important due to rich contents of low frequency in ground motion signals. In particular, the impulsive properties of the ground motion recorded in near-fault zones are susceptible to the high-pass filtering, and thus selecting a reasonable

In engineering practice, it is a common that rocks are subjected to cyclic loading. The mechanical properties of rock materials under tiered, single-level, and multi-level cyclic load regimes (i.e., with different frequency, minimum stress, and amplitude) were numerically investigated by using a dynamic constitutive model for rock materials. A comparison between these loads from the aspects of stress-strain

The problem of estimating seismic ground deformation is central to state-of-practice procedures of designing and maintaining infrastructure in earthquake-prone areas. Particularly, the problem of estimating the displacement field in a soft shallow layer overlying rigid bedrock induced by simple shear wave excitation has been favored by engineers due to its simplicity combined with inherent relevance

Batter piles are widely used in geotechnical engineering construction. Observations regarding the performance of batter piles in seismic hazards are controversial, and few studies have evaluated batter piles in liquefiable and laterally spreading ground. Three centrifuge experiments were performed to gain a better understanding of the performance of batter piles in liquefiable ground and to reveal

In shaking table tests, appropriate boundary conditions are required in order to simulate semi-infinite seismic soil deposit responses within a finite size soil container. In this study, a laminar shear container with variable stiffness, constructed with a stack of steel hollow frames supported by ball bearings and bolts, was designed. The stiffness of the container can be changed by adjusting the

Investigation of propagation of surface waves, and also interfacial waves in a saturated either homogeneous or coated half-space in the framework of a simplified version of Biot theory known as u−p formulation is the target of this paper. Both the half-space and the coating are fluid-saturated transversely isotropic in both transport and elastic points of view. The coupled fluid continuity equation

Many soil-structure interaction systems experience a three-dimensional loading condition (i.e. shear coupling) at their interfaces. In this study, an elasto-plastic constitutive formulation for interfaces in soil-structure interaction problems is proposed considering the effects of 3D shear coupling loading conditions. The proposed model is capable of simulating granular soil-structure interfaces for

Shear-critical reinforced concrete structures such as older columns with insufficient transverse reinforcement details or short columns are found to be vulnerable to earthquake loading. Meanwhile, in the aggressive environment, RC structures tend to be more vulnerable to earthquake since corrosion of reinforcements will cause deterioration of the material properties. In the present study, a new framework

Undrained stress-controlled cyclic triaxial and direct simple shear test data on five different clean sands was analyzed in terms of dissipated and stored strain energy. A new method was developed to calculate damping ratio from undrained stress-controlled tests and its plausibility was examined with the help of pore water pressure data. Results from different methods in the literature to calculate

The high-speed railway (HSR) in China has developed rapidly in recent years. However, HSR bridges have to face the challenge of earthquakes since China is one of the most earthquake-prone countries in the world. Bearing is the key component in the HSR bridge, and using isolation bearing instead of common bearing (non isolation bearing) can provide bridge the better seismic performance. To improve seismic

Earthquakes are not isolated events and, typically, dominated by a larger-magnitude excitation (Mainshock – MS) and many smaller-magnitude motions (Aftershock – AS). Most often, such destructive events bring more damage than a single strong motion. Nowadays, many existing non-seismic designed RC structures are classified as either functional-obsolete or sub-standards. The seismic performance of these

Accurate prediction of tunnel behavior and damage states under seismic loading remains a challenge. This study carried out tunnel behavior and risk assessment using numerical dynamic analysis on a NATM tunnel. A hypoplastic model that considers intergranular strain was calibrated for a particular sand using experimental tests and numerical simulations. It then was used in numerical simulations for

Accurate evaluation of dynamic resistance provided by the surrounding soil is the key to determining the dynamic performance of the pile foundation, especially for long piles. A new method is proposed to evaluate the dynamic pile-side soil resistance (DPSR). A dynamic coupled model of the pile-soil system is established considering the three-dimensional nature of the surrounding soil. Analytical solutions

When constructing a new railway line, its long length means there are significant financial implications associated with determining the geodynamic ground properties. Therefore, this paper presents recommendations to optimize the efficiency and depth of such a geotechnical site investigation. Firstly, a numerical analysis is performed to investigate the effect of soil layering, soil stiffness and track

The paper presents the Hermit-type radial basis reproducing kernel particle method (Hermit-type RRKPM) for wave propagation. The Hermit-type radial basis function is employed to construct the approximating function, which can reduce the adverse effect of different reproducing kernel functions (RKFs) on computational accuracy and improve stability in the problem domain and on the boundary of the domain

Liquefaction is a major cause of coseismic damages, occurring irregularly over hundreds or thousands of square kilometers in large earthquakes. Large variations in the extent and location of liquefaction have been observed in recent earthquakes, motivating the need for prediction methods that consider the spatial heterogeneity of geologic deposits at a regional scale. Contemporary regional-scale liquefaction

The present study proposes a simplified analytical solution based on Euler Bernoulli's beam theory to investigate the influence of seismic landslide on buried continuous pipeline. Firstly, the differential equation of the beam (pipe) is derived considering the beam is resting on elastic foundation (soil spring) and then the complete solution (both complementary function and particular integral) of

In this paper, an efficient method is proposed for constructing the seismic fragility curves of bridge piers, in which the dynamical reliability assessment is developed from methods of moment. The main procedure for constructing seismic fragility curves consists of four steps. First, the non-stationary seismic acceleration process samples are simulated by the random function-spectrum representation

The traveling wave resonance phenomenon exhibits in the seismic response of the symmetric bridge structure. However, there is a scarcity of shaking table tests validating the traveling wave resonance. A 1/70-scale pile-soil-cable-stayed bridge model was fabricated following the preliminary design of a cable-stayed bridge with a main span of 1400 m. Shaking table tests were performed to verify the traveling

Nonlinear site response modeling is a crucial aspect of Probabilistic Seismic Hazard Analysis. Site amplification models routinely rely on a rock intensity measure to characterize the strength of the bedrock motion. However, the adequacy of such intensity measures towards predicting amplifications across the oscillator period range has not been investigated in the literature. This paper analyzes the

Owing to the good strength and stability of loess under dry and static conditions, many buildings in loess areas are built on slopes in western China, i.e., an earthquake-prone area. A phenomenon was discovered in the Minxian-Zhangxian Ms 6.6 earthquake and Jiuzhaigou Ms 7.0 earthquake, that is, the damage to the buildings on the top of the slope was more serious than that on the horizontal site, and

A series of dynamic direct shear tests and triaxial tests were conducted to investigate the dynamic properties of the warm frozen soil along the Qinghai-Tibet railway. The relationship between dynamic shear stress and dynamic shear strain of frozen soil under relatively high negative temperature is given according to the test results. The influences of cooling temperature, vertical pressure, confining

In this study, a large amount of stress-dilatancy data of Karlsruhe fine sand were examined at first, where it was found that the stress-dilatancy behaviour of Karlsruhe fine sand depended on its void ratio and pressure. To capture such state-dependent stress-dilatancy behaviour, the fractional-order dilatancy equation and Li and Dafalias [1]'s dilatancy equation, were adopted and compared. In addition

This study is aimed to reconstruct displacements from measured accelerations based on a low-frequency attenuation (LFA) algorithm. The integration of acceleration is conducted directly in frequency domain and the integral accuracy is governed by an accuracy control factor (ACF). A finite element simulation is conducted to compare the integral accuracy of this algorithm with those of several other conventional

Evaluation of the impedance functions and internal forces in various modes of vibration form an important step in the design of pile supported structures subjected to dynamic loads. This study tries to assess the variation in impedance functions and load distribution characteristics when a ground contacting pile cap is introduced over single and group piles. A substructuring method-based soil structure

Pseudo-static slope stability procedures are often employed to evaluate the seismic performance of slope systems, at least in the initial evaluation stages. To yield meaningful results, these methods should rely on parameters that are representative of the existing seismic demand and the properties of the slope system being evaluated. This study proposes a performance-based probabilistic procedure

In this work, nonstationary ground motion coherency analysis and modeling are performed using wavelet analysis and relevance vector machine regression. Earthquake ground motion data from four events recorded at dense seismograph SMART-1 array in north-south and east-west horizontal directions are used to investigate the lagged coherency behavior. Wavelet transform is used to compute the nonstationary